An Intense, Continuous Cold Atom Source

TL;DR

This paper presents a method to generate an intense, continuous cold atom beam using a cooled helium jet seeded with lithium, achieving high flux and brightness suitable for advanced atomic physics experiments.

Contribution

The authors demonstrate a novel continuous cold atom source with high flux and brightness, combining a cooled helium jet with magnetic focusing, validated by simulations.

Findings

Achieved a flux of 2.3×10^{12} atoms/s

Measured brightness of 4.1×10^{19} m^{-2}s^{-1}sr^{-1}

Projected tenfold increase in flux with improved vacuum

Abstract

We demonstrate an intense, continuous cold atom beam generated via post nozzle seeding of a supersonic helium jet with $^7$Li atoms. The nozzle is cooled to about 4.4 K to reduce the forward velocity of the atoms. The atomic beam is brought to a focus 175 cm from the nozzle by a 10 cm bore diameter magnetic hexapole lens. Absorption and fluorescence imaging of the focus show a flux of $2.3(4) \times 10^{12}$ atoms/s, brightness of $4.1(7)\times 10^{19}$ $\textrm{m}^{-2}\textrm{s}^{-1}\textrm{sr}^{-1}$, forward velocity of 211(2) m/s, and longitudinal temperature of 7(3) mK. Results agree with a Monte Carlo simulation of the seeding dynamics and a particle tracing simulation of the atom lens. We project that 10 times higher flux would be possible with improved vacuum system design. Our method should provide a useful high-brightness source for atom-optical and other atomic and molecular physics applications.